Impact on environment, economy, and public health

 

Pollution of the hydrosphere is a major problem. When we think of pollution, we sometimes only think of things like plastic, bottles, oil and so on. But any chemical that is present in the hydrosphere in an amount that is not what it should be is a pollutant. Animals and plants that live in the earth's water bodies are specially adapted to surviving within a certain range of conditions. If these conditions are changed (e.g. through pollution), these organisms may not be able to survive. Pollution then, can affect entire aquatic ecosystems. The most common forms of pollution in the hydrosphere are waste products from humans and from industries, nutrient pollution e.g. fertiliser runoff which causes eutrophication (an excess of nutrients in the water leading to excessive plant growth) and toxic trace elements such as aluminium, mercury and copper to name a few. Most of these elments come from mines or from industries

We mentioned earlier that only a very small percentage of the hydrosphere's water is available as freshwater. However, despite this, humans continue to use more and more water to the point where water consumption is fast approaching the amount of water that is available. The situation is a serious one, particularly in countries such as south africa which are naturally dry and where water resources are limited. It is estimated that between 2020 and 2040, water supplies in south africa will no longer be able to meet the growing demand for water in this country. This is partly due to population growth, but also because of the increasing needs of industries as they expand and develop. For each of us, this should be a very scary thought. Try to imagine a day without water... Difficult isn't it? Water is so much a part of our lives, that we are hardly aware of the huge part that it plays in our daily lives.

As populations grow, so do the demands that are placed on dwindling water resources. While many people argue that building dams helps to solve this water-shortage problem, there is evidence that dams are only a temporary solution and that they often end up doing far more ecological damage than good. The only sustainable solution is to reduce the demand for water, so that water supplies are sufficient to meet this. The more important question then is how to do this.

Water ensures the existence of living organisms on earth, and the course of their life processes. It is part of the cells and tissues of any animal and plants. On average, water is about 90% of the mass of all plants and 75% of the mass of animals. Climate and weather on earth is largely dependent on and determined by the presence of water spaces and water vapor content in the atmosphere.

In human water are widely used. Water is used in industry, serves as coolants used in the construction and. Agricultural activities associated with the consumption of vast quantities of water. Rivers, canals, lakes — important means of communication.

Historically, people have always settled near water sources. They provided them with fresh water, were given water for irrigation and production development. In the middle of xx century, mankind has created new opportunities in the sustainable provision of water resources: they built reservoirs and canals, artesian wells were drilled. Along with increases in capacity and the emergence of an increasing need for fresh water — has grown, and the ability to waste water, waste, without looking back. In terms of everyone on the planet quantity intake increased from 140 to 780 liters per day. And in all the calculations of water consumption, taking into account agriculture, industry and domestic needs, never taken into account other important consumer of water — environment.

As a result of irrational consumption expenditure of the water began to exceed the rate of recurrence. Rivers no longer reach the sea, drying lakes, depleting aquifers, degraded ecosystems — all due to overruns in the water and the underestimation of the value of this resource in ill-considered policy of consumption.

2. The Aral Sea (Kazakh: Арал Теңізі Aral Teñizi; Uzbek: Orol dengizi; Russian: Ара́льское море, tr. Aral'skoye Morye; IPA: [ɐˈralʲskəjə ˈmorʲɪ]; Tajik: Баҳри Арал Bahri Aral; older Persian: دریاچه خوارزم‎‎ Daryâche Khârazm; Mongolian: Арал тэнгис) was an endorheic lakelying between Kazakhstan (Aktobe and Kyzylorda Regions) in the north and Uzbekistan (Karakalpakstan autonomous region) in the south. The name roughly translates as "Sea of Islands", referring to over 1,100 islands that once dotted its waters; in the Turkic languages aral means "island, archipelago". The Aral Sea drainage basin encompasses Uzbekistan and parts of Tajikistan, Turkmenistan, Kyrgyzstan, Kazakhstan, Afghanistan and Pakistan.^[1]

Formerly one of the four largest lakes in the world with an area of 68,000 km² (26,300 sq mi), the Aral Sea has been steadily shrinking since the 1960s after the rivers that fed it were diverted by Soviet irrigation projects. By 2007, it had declined to 10% of its original size, splitting into four lakes – the North Aral Sea, the eastern and western basins of the once far larger South Aral Sea, and one smaller lake between the North and South Aral Seas.^[4] By 2009, the southeastern lake had disappeared and the southwestern lake had retreated to a thin strip at the western edge of the former southern sea; in subsequent years, occasional water flows have led to the southeastern lake sometimes being replenished to a small degree.^[5] Satellite images taken by NASA in August 2014 revealed that for the first time in modern history the eastern basin of the Aral Sea had completely dried up.^[6] The eastern basin is now called the Aralkum Desert.

In an ongoing effort in Kazakhstan to save and replenish the North Aral Sea, a dam project was completed in 2005; in 2008, the water level in this lake had risen by 12 m (39 ft) compared to 2003. Salinity has dropped, and fish are again found in sufficient numbers for some fishing to be viable. The maximum depth of the North Aral Sea is 42 m (138 ft) (as of 2008).

The shrinking of the Aral Sea has been called "one of the planet's worst environmental disasters". The region's once-prosperous fishing industry has been essentially destroyed, bringing unemployment and economic hardship. The Aral Sea region is also heavily polluted, with consequential serious public health problems.

Salinization of Soil

A sharp increase in salinization of lands is one of the most negative consequences of Aral Sea crisis. Groundwater level decline also caused salt accumulation in the subsoils. This led to increase in salt deposition in the soil profiles and reeds were replaced by grass saltworts as a result, which prevented anything from growing there. Salinization of soils accelerated the desertification process as it accompanied the sharp decline in groundwater level and the drying of subsoils. This eventually lead to soil erosion, one of the primary reasons for extensive fertilizer use. In turn, these abusive fertilizing practices further deteriorated soils and created pollution that went both into the Aral Sea through groundwater circulation and into the air through dust storms.

In 1987, the continuing shrinkage split the lake into two separate bodies of water, the North Aral Sea (the Lesser Sea, or Small Aral Sea) and the South Aral Sea (the Greater Sea, or Large Aral Sea) In June 1991, Uzbekistan gained independence from the Soviet Union. Craig Murray, a UK ambassador to Uzbekistan in 2002, described the independence as a way for Islam Karimov to consolidate his power rather than a move away from a Soviet-style economy and its philosophy of exploitation of the land. Murray attributes the shrinkage of the Aral Sea in the 1990s to Karimov's cotton policy. The government maintained a massive irrigation system which Murray described as massively wasteful, with most of the water being lost through evaporation before reaching the cotton. Crop rotation was not used, and the depleted soil and monoculture required massive quantities of pesticides and fertilizer. The runoff from the fields washed these chemicals into the shrinking sea, creating severe pollution and health problems. As the water supply of the Aral Sea decreased, the demand for cotton increased and the Soviet reacted by pouring more pesticides and fertilizer onto the land. Murray compared the system to the slavery system in the pre-Civil War United States; forced labor was used, and profits were siphoned off by the powerful and well-connected. Murray contrasts this to Kazakhstan, where the cotton industry had been privatized.

By summer 2003, the South Aral Sea was vanishing faster than predicted. In the deepest parts of the sea, the bottom waters were saltier than the top, and not mixing. Thus, only the top of the sea was heated in the summer, and it evaporated faster than would otherwise be expected. In 2003, the South Aral further divided into eastern and western basins.

In 2004, the Aral Sea's surface area was only 17,160 km² (6,630 sq mi), 25% of its original size, and a nearly five-fold increase in salinity had killed most of its natural flora and fauna. By 2007, the sea's area had further shrunk to 10% of its original size, and the salinity of the remains of the South Aral had increased to levels in excess of 100 g/l.^[4] (By comparison, the salinity of ordinary seawater is typically around 35 g/l; the Dead Sea's salinity varies between 300 and 350 g/l.) The decline of the North Aral has now been partially reversed following construction of a dam (see below), but the remnants of the South Aral continue to disappear and its drastic shrinkage has created the Aralkum, a desert on the former lake bed.

The inflow of groundwater into the South Aral Sea will probably not in itself be able to stop the desiccation, especially without a change in irrigation practices.^[23] This inflow of about 4 km³ (0.96 cu mi) per year is larger than previously estimated. The groundwater originates in the Pamirs and Tian Shan Mountains and finds its way through geological layers to a fracture zone^[24] at the bottom of the Aral.

3. The ecosystems of the Aral Sea and the river deltas feeding into it have been nearly destroyed, not least because of the much higher salinity. The receding sea has left huge plains covered with salt and toxic chemicals – the results of weapons testing, industrial projects, and pesticides and fertilizer runoff – which are picked up and carried away by the wind as toxic dust and spread to the surrounding area. As a result, the land around the Aral Sea is heavily polluted, and the people living in the area are suffering from a lack of fresh water and health problems, including high rates of certain forms of cancer and lung diseases. Respiratory illnesses, including tuberculosis (most of which is drug resistant) and cancer, digestive disorders, anaemia, and infectious diseases are common ailments in the region. Liver, kidney, and eye problems can also be attributed to the toxic dust storms. These dust storms also contributed to the lack of fresh water since the salt melted the glaciers faster and not enough moisture was in the air to help replace them. The dust storms increased the melting levels for the glaciers by 12 times the normal rate.^[24] Health concerns associated with the region are a cause for an unusually high fatality rate amongst vulnerable parts of the population. The child mortality rate is 75 in every 1,000 newborns and maternity death is 12 in every 1,000 women.^[25] A overuse of pesticides on crops was one of the contributing factors to this. To get their crops to grow their pesticide use would have to exceed health standards and could be twenty times more than the national average.^[24] Crops in the region are destroyed by salt being deposited onto the land and are flushed with water at least 4 times a day to try and remove the salinity from the soils.^[24] Vast salt plains exposed by the shrinking Aral have produced dust storms, making regional winters colder and summers hotter.

The Aral Sea fishing industry, which in its heyday had employed some 40,000 and reportedly produced one-sixth of the Soviet Union's entire fish catch, has been devastated, and former fishing towns along the original shores have become ship graveyards. The town of Moynaq in Uzbekistan had a thriving harbor and fishing industry that employed about 30,000 people;^[30] now it lies miles from the shore. Fishing boats lie scattered on the dry land that was once covered by water; many have been there for 20 years. The only significant fishing company left in the area has its fish shipped from the Baltic Sea, thousands of kilometers away.^[31]

Also destroyed is the muskrat-trapping industry in the deltas of the Amu Darya and Syr Darya, which used to yield as many as 500,000 pelts a year.^[

Lecture 17.